1. Field of the Invention
Embodiments of the present invention relate to a semiconductor device, and more particularly relates to a semiconductor device including a roll call circuit.
2. Description of Related Art
A semiconductor memory device such as a DRAM (Dynamic Random Access Memory) generally includes a large number of memory cells, and thus it is hard to manufacture the device with all the memory cells working properly. For this reason, most semiconductor memory devices include a redundant circuit for replacing a defective memory cell. When an access request to the defective memory cell is issued, the semiconductor memory device performs an access to the redundant circuit instead of performing the access to the defective memory cell. This enables access to a memory address corresponding to the defective memory cell, so that a user can handle it as a semiconductor memory device with no defect.
Meanwhile, from a viewpoint of a device designer, there is a demand to check whether each address is replaced by the redundant circuit by a test operation. To meet this demand, a roll call circuit is often provided (see Japanese Patent Application Laid-Open No. H05-47196).
A semiconductor device described in Japanese Patent Application Laid-Open No. H05-47196 includes a plurality of memory arrays. When performing a roll call test, the same address is supplied to the memory arrays, so that the roll call test is performed in parallel for the plurality of memory cell arrays.
However, the semiconductor device described in Japanese Patent Application Laid-Open No. H05-47196 masks roll call data obtained in parallel from the plurality of memory arrays except for selected roll call data, by which the selected roll call data is output to outside. Therefore, it is equivalent to conduct the roll call test for substantially a single memory cell, and thus it takes a long time to complete the roll call test for all addresses.